So Nikon is rumored to be releasing another F4 lens (trend?) that is going to be targeted at Fx with a 24-120mm focal range with VR. So I am wondering think F4 will be nikons new trend this year? Since it seems Canon has F4 and F2.8 of all of it's lenses. I wonder how could of subject isolation you can get with the F4 lens (I know it depends on element design also). I remembered some of my consumer level lenses were 3.5-xx and were never really that good at subject isolation at 3.5 or 4 but I know my 70-200 still does well at F4. Thoughts?